High 8.7Published Apr 3, 2025

CVE-2025-31115XZ has a heap-use-after-free bug in threaded .xz decoder

Updated under an hour ago (2026-10-19 08:30 UTC)

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It affects tukaani-project xz and 3 other products. Add what you run to find out whether that includes you.

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Every CVE for tukaani-project xz

Exploited in the last 30 days

XZ Utils provide a general-purpose data-compression library plus command-line tools. In XZ Utils 5.3.3alpha to 5.8.0, the multithreaded .xz decoder in liblzma has a bug where invalid input can at least result in a crash. The effects include heap use after free and writing to an address based on the null pointer plus an offset. Applications and libraries that use the lzma_stream_decoder_mt function are affected. The bug has been fixed in XZ Utils 5.8.1, and the fix has been committed to the v5.4, v5.6, v5.8, and master branches in the xz Git repository. No new release packages will be made from the old stable branches, but a standalone patch is available that applies to all affected releases.

CVSS: 8.7 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-366, CWE-416, CWE-476, CWE-826
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Not yet received
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

tukaani-project xz tukaani_project:xz (from the name)	from 5.3.3alpha, < 5.8.1	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.5	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.5	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.5	CISA ADP

References

https://github.com/tukaani-project/xz/security/advisories/GHSA-6cc8-p5mm-29w2x-refsource-confirm
https://github.com/tukaani-project/xz/commit/d5a2ffe41bb77b918a8c96084885d4dbe4bf6480x-refsource-misc
https://tukaani.org/xz/xz-cve-2025-31115.patchx-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.